+// --- Layout ---
+extern size_t _udi_marshal_step(void *buf, size_t cur_ofs, udi_layout_t **layoutp, va_list *values);
+extern size_t _udi_marshal_values(void *buf, udi_layout_t *layout, va_list values);
+
+// --- Buffers ---
+extern udi_buf_t *_udi_buf_allocate(const void *data, udi_size_t length, udi_buf_path_t path_handle);
+